The present invention relates to phenol removal and, in particular to a process of removing phenols from an aqueous solution, such as a biomass-hydrolyzate medium.
The efficiency of methods for the selective removal of biomass-derived-phenolic-compounds, from an aqueous feedstock is a limiting step in any microbial process for the conversion of biomass dissolved sugars into fuels or chemicals. It is also desirable in some applications to remove these aromatic compounds because they contaminate fresh water streams after a forest fire, and process water used in the production or recycling of pulp and paper.
A distinct disadvantage of the prior art methods has heretofore been the inefficiency and low selectivity of the separation process when applied to an aqueous hydrolyzate. One prior method solution involves an extraction of the aqueous hydrolyzate using a series of organic solvents, such as ethyl acetate, TUF or methyl isobutyl ketone. However, in an organic solvent extraction, the water soluble biomass-derived-phenolic compounds remain in the aqueous phase with the dissolved sugars. Another method comprises filtration of the aqueous hydrolyzate through an activated carbon filter. However, with this method, a disadvantage is that the activated carbon removes, in addition to the phenol component, many other organic compounds resulting in an inefficient process.
Therefore, it is an object of the invention to provide a process for removing phenols from an aqueous solution.
It is a further object of the invention to provide a process for the removal of phenols from dissolved sugars in an aqueous biomass-hydrolyzate medium.
It is a yet another object of the invention to provide a biomass pretreatment process for removing lignin-derived phenolic compounds from dissolved sugars in an aqueous biomass hydrolyzate medium, the process of which is capable of regeneration.
The foregoing specific objects and advantages of the invention are illustrative of those, which can be achieved by the present invention and are not intended to be exhaustive or limiting of the possible advantages which can be realized. Thus, those and other objects and advantages of the invention will be apparent from the description herein or can be learned from practicing the invention, both as embodied herein or as modified in view of any variations which may be apparent to those skilled in the art.
To overcome the problems of the prior art methods and in accordance with the purpose of the invention, as embodied and broadly described herein, a process for removing phenols from an aqueous solution is provided which comprises the steps of contacting a mixture comprising the solution and a metal oxide, forming a phenol metal oxide complex, and removing the complex from the mixture.